スピンバルブ膜を用いたCPP(Current-perpendicular-to-plane)素子のGMR特性

概要

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The CPP (current-perpendicular-to-plane) element using spin-valve (SV) film is adaptable to many applications because it does not exhibit the problems of multilayer GMR, such as generation of hysteresis and difficulty in controlling the magnetic domain. We investigated the ΔR_N and MR ratio of CPP elements, which are determined by the structure of the SV film and thickness of the magnetic layers. By introducing synthetic ferrimagnetic single SV to the CPP element, we kept ΔR_N small (0,49 mΩμm^2) while achieving an MR ratio of 15% (1.6 times the value for the CIP). With dual SV structure for the CPP element, the ΔR_N and MR ratio peaked at 3,85 mΩμm^2 and 40%, when the total thickness of the free side pinned layer and free layer was around 18 nm. This result was caused by increasing the number of magnetic/non-magnetic interfaces and enhancing of bulk scattering. When the total thickness of free side pinned layer and free layer exceeds 18 nm, ΔR_N, and MR ratio drop because of increased spin diffusion. Applying a synthetic ferrimagnetic dual SV structure would provide a ΔV of 3.2 mV with an element size of 0.01μm^2.
社団法人日本磁気学会の論文
2001-04-15